Thin, substantially flat articles are difficult to handle, especially if they are small, light in weight and vulnerable to physical damage. It is conventional, although tedious, to handle such articles with manual tweezers. For example, if a flat article rests on a flat surface, it is tedious to insert a tip of a tweezer under the article. After pickup, excess finger pressure on the tweezer may cause gouges and scratches in either of two major surfaces of the article.
The electronics industry is typical of a field where such thin, substantially flat articles are encountered. For example, lids on chip carriers may be only about b 6 to 1O mm square, about 0.15 to 0.25 gram in weight and may have a delicate bonding frame on a major surface. Such lids are assembled to chip enclosures in multiple arrays in semiautomatic machines. The lids and enclosures are fed into the machines and one of each are registered and clipped together for reflow bonding. A problem is to handle the lids for loading in an efficient manner without damaging the bonding frame.
In a presently popular technique, the lids are handled in tubular magazines, often called sticks. The tubes are typically square in cross section, about 25 to 30 cm long and have initially open ends. Caps or plugs may be utilized to close the ends after the tubes are loaded with a column of lids. A problem is to load the lids, all facing in the same direction, with back-to-front contact of major surfaces in a tube.
The lids are typically made from a thin sheet of metal alloy or ceramic material which is later severed into individual portions. A frame of bonding material may be applied to each lid portion before or after separation from other lids. When completed, the lids lie in an edge-to-edge array, typically with bonding surfaces facing upward in a flat tray. Heretofore, tweezer tools or vacuum probes were typically utilized to manually load the lids, one at a time, into the tubes. It will be appreciated that such loading is inefficient, expensive and risky to bonding frames.
Accordingly, it is desirable to provide new and improved expedients for assembling articles, especially flat articles, in a tube. Lids for chip carriers are exemplary of flat articles requiring special handling because they are small, light in weight and often brittle. Expedients are needed to efficiently assemble such lids, one at a time, preferably in a vertically disposed tube.